| "The sign of teh devil." Two Walbro 255L/H High Pressure pumps were ordered shortly after the previous dyno session where the TRE Performance pumps were showing that they weren't keeping up. The Walbros were installed and tested over the weekend in a few street pulls with expected results. A fuel pressure sender was installed into the fuel system and linked into the Blitz SBC-iC's input harness so that fuel pressure can be displayed and datalogged. Additionally, I picked up the optional harness for the SBC-iC which allows for 3 additional auxiliary inputs. I strapped the PLX Devices wideband's output signal into the SBC for easy monitoring and datalogging. Made my trip up to the dyno this morning - temperatures were 91 degrees in the dyno room, 31% humidity - blech. Green pull is at 24psi. Red pull is at ~28psi, and the blue pull is where the RPS Sport 6-puck clutch just had enough. It appears that in the red pull, the clutch was already showing a little sign of slippage - right at 5750RPM you see that sharp rise in torque - this is right where the clutch stopped slipping and the engine's inertia was absorbed through the driveline. 
I had a feeling that the Sport clutch was nearing its limits the last time at the dyno - pushing 550ft/lbs at the wheel is a bit much to ask of this clutch, but it appears that a brand new Sport clutch will hold approximately 590RWTQ before it lets loose. Pretty amazing clutch if you ask me. :) Here is the video of the 666RWHP pull:
[ http://ashspecz.com//ashspec/DYNO%20Charts/AshsZ%203-21-06/Videos/666RWHP.mpg ] Here's the following pull where the clutch decides it's had enough:
[ http://ashspecz.com//ashspec/DYNO%20Charts/AshsZ%203-21-06/Videos/ClutchSlip.mpg ] I am sitting on the fence about what to do for a clutch. I want a lightweight flywheel setup - I have the RPS segmented flywheel and I'm very reluctant to give that up - its an excellent product. It would be nice to see RPS produce a carbon clutch setup that uses the segmented flywheel, but instead of the steel friction plates, carbon plates as replacements. It would also be nice to see RPS produce a billet aluminum pressureplate assembly for this flywheel that also has a carbon-faced friction ring, and a carbon clutch disc, sprung hub design - preferably with the enclosed spring retainer plate to prevent that item from going to pieces. A billet PP housing will likely be lighter than the stamped-steel housing currently used. It would be nice to know what the exact friction properties of these carbon-carbon & semi-carbon (carbonclaw) materials are. From what I have read, it sounds like this material, square inch per square inch and pound of clamping per pound of clamping, will outperform any other type of material available. If this is truly the case, it appears that making some modifications to existing product (carbon inserts in the flywheel, carbon clutch disc) and production of a new pressureplate (lightweight billet aluminum and, say, an RPS sport pressureplate diaphragm spring), you will effectively create a lighter clutch assembly that will have a greater torque-holding capacity as well as a light clutch pedal. All of these characteristics being properties I desire for my intended uses of the vehicle. A snippet from a little google searching on the subject:
[ http://www.srbpower.com/rps/separating-the-facts-from-friction.php ]
The highest technology known to man in fiction surface is Carbon-Carbon. Carbon-carbon composites consist of highly-ordered graphite fibers embedded in a carbon matrix. C-C composites are made by gradually building up a carbon matrix on a fiber preform through a series of impregnation and pyrolysis steps or chemical vapor deposition. C-C composites tend to be stiffer, stronger and lighter than steel or other metals. The most important class of properties of carbon-carbon composites is their thermal properties. C-C composites have very low thermal expansion coefficients, making them dimensionally stable at a wide range of temperatures, and they have high thermal conductivity. C-C composites retain mechanical properties even at temperatures (in non-oxidizing atmospheres) above 2000°C. They are also highly resistant to thermal shock, or fracture due to rapid and extreme changes in temperature. Our hard core clients who uses our C/C technology are racers that are utilizing this amazing break-through by doing 2nd gear burnouts, 2nd gear launches, line lock assisted launch with the clutch semi disengaged to load the engine to make positive boost 15~30 psi in 2nd gear!!! Others do 1st gear 7000+ RPM clutch dumps to get the clutch to slip for a fraction of a second for it not to break the tires loose. All on a 2 ton AWD car making 750+AWHP 200+ times at the track daily driven (3000GT-VR-4 Dynamic Racing), Supra 2JZ with 1200lbs of torque on a dyno slipping (Powerhouse/MVP), Viper GTS Supercharged cranking out 1000lbs of torque daily driven (Palo Castalano/ Heffner Performance) to name a few. I see the confusion that some of these peoples judgment are being made. The Exedy or OS Giken or ATS and any one else except for Tilton is using the technology RPS created 5yrs ago (CarbonClaw). This stuff is a carbon with ceramic mixture and will be a higher coefficient than the regular friction materials available to them. The Semi-Carbon is what the true name is called, cause of the friction mating surface is metal and can be very costly to manufacture even in this technology. But the affect is still the same way of conventional clutches not holding up to heat and will glaze over if slipped too much. The disc that is carbon will glaze over, hence it is more streetable when it heats up, therefore will not hold up to the higher boost it will slip itself to death. The product’s technology is still a long shot away from the real McCoy Carbon-Carbon. This is the only stuff that NASA, F-1, Top Fuel, WRC, and NASCAR use.
From my perspective, I see potential for a new clutch product. Something that is going to offer great torque handling capacity, brick sh~thouse ruggedness, lightweight assembly, light clutch pedal....... Maybe another BIY project.... just my $.02 though.. Anyhow, hope you enjoyed the read and hopefully it has sparked some thoughts. Thanks!
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[ agpowers@bellsouth.net ] Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the tailor.
Albert Einstein
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AshsZ-II Ultimate Street Z: 666RWHP & 602RWTQ - 
21:25:22 03/21/06
